Paweł is available for hire
Hire PawełPaweł Jędrzejczyk
Verified Expert in Engineering
Front-end Developer
Gdańsk, Poland
Toptal member since May 4, 2022
Bio
Paweł is a lead JavaScript engineer working on web apps since 2006. Currently working with React and TypeScript, he is passionate about creating great UI/UX. Paweł is an amazing, team-oriented specialist with ingenious web skills, an eye for detail, and excellent interpersonal competencies, always looking for a way to add value to the project.
Portfolio
An Online Freelance Agency
TypeScript, A/B Testing, Amplitude, Gatsby, Next.js, Optimizely...
Netguru
TypeScript, React, Webpack, Styled-components, Redux, Redux-Saga, SCSS
BR-DESIGN
JavaScript, Webpack, Docker, Vagrant, Redux, React, HTML5, CSS
Experience
- Private NPM Modules - 7 years
- UI Components - 7 years
- Design Systems - 7 years
- React - 7 years
- Jest - 5 years
- Storybook - 5 years
- TypeScript - 4 years
- Next.js - 3 years
Availability
Part-time
Preferred Environment
React, TypeScript
The most amazing...
...thing I've developed is a React-based online dating app that reached 1+ million users.
Work Experience
Lead JavaScript Engineer
2017 - 2022
An Online Freelance Agency
- Created and maintained internal npm packages that allowed better code sharing across multiple projects.
- Managed and maintained a design system using Storybook that made it easy to build components in isolation, increased developer awareness of existing features, and served as living documentation.
- Designed and developed an A/B testing tool using the content management system (CMS), Sanity, and Amplitude to test different versions of the components across the web and mobile apps, which led to increased revenue and reduced churn.
- Refactored the apps to use TypeScript, which improved the code quality and significantly reduced the number of errors, making onboarding new people to the project more accessible and increasing developers' confidence in developing new features.
- Worked on-sell pages rewrite from legacy WordPress to Gatsby and React with static site generation backed by Sanity headless CMS, improving the page load speed and other key performance metrics.
Technologies: TypeScript, A/B Testing, Amplitude, Gatsby, Next.js, Optimizely, Styled-components, React, Redux, Redux-Saga, Node.js
Senior Front-end Developer
2016 - 2017
Netguru
- Took part in pre-sale calls as an engineering expert to gather client requirements which led to increased thrust and gave more confidence to the client.
- Managed and maintained a front-end engineer growth checklist that allowed junior and middle-level developers to level up their skills more quickly by learning what was actually needed.
- Prepared code tasks for new candidates and interviewed over 50 developers.
- Provided React and React Native expertise for native mobile and back-end developers wanting to make a switch in their careers.
- Conducted weekly front-end related meetings to discuss new tools, ideas, and issues and build better relations in the team.
- Worked on the homepage optimization of a multi-language online marketplace for household-related services, a web app used by over 100,000 users across 10 countries.
- Developed internal tools that allowed setting up projects more easily while keeping all the company-wide rules and code patterns.
Technologies: TypeScript, React, Webpack, Styled-components, Redux, Redux-Saga, SCSS
Front-end Engineer
2012 - 2016
BR-DESIGN
- Created the web client-side experience for an online dating app with 1+ million users.
- Built a real-time chat set on a Node.js server and WebSockets and a gradual engagement or lazy registration feature that offers a way to use the app before creating an account.
- Owned the development of a web app for health professionals with an online drug database allowing for checking the interactions between different substances with a quick and easy search.
- Developed a web app for United Parcel Service (UPS) that allowed to prepare branded document templates that were later used by 30+ national branches to generate a web page and print-ready, high-quality PDF files translated to different languages.
- Created and maintained a development environment based on Vagrant and Docker that simplified setting up complex projects by running just one command-line interface (CLI) command.
Technologies: JavaScript, Webpack, Docker, Vagrant, Redux, React, HTML5, CSS
Web Engineer
2006 - 2012
Freelance
- Developed and designed a WordPress website for a company with a catalog of over 3,000 products ranging from jewelry to wedding dresses. Also provided the maintenance of the website for a couple of years.
- Designed and built a WordPress website for a music band. The website featured a contact form, an audio and video player, and a photo gallery.
- Held the development and design of a website for a company offering houses for rent. The website included a contact form and a photo gallery.
- Created and designed a WordPress website for an advertising photography services company. The work included search engine optimization.
Technologies: HTML, CSS, jQuery, PHP, WordPress, Apache, NGINX, JavaScript, PSD to HTML
Experience
Openfit | Home Fitness on Demand Classes App
https://www.openfit.comOpenfit is a health and fitness app that offers live classes, on-demand workouts and programs, and nutritional tracking.
The project sought a React web and mobile app in React Native. I was the lead JavaScript developer responsible for all web experiences, also helping with the mobile app.
I created and maintained internal npm packages that allowed better code sharing across multiple projects while managing and maintaining a responsive UI components library using Storybook.
I also worked on-sell pages, rewriting from legacy WordPress to Gatsby and React with static site generation backed by Sanity headless CMS that improved the page load speed and other key performance metrics.
Then, I designed and developed an A/B testing tool using Sanity CMS and Amplitude to test different versions of components across the web and mobile app, which led to increased revenue and reduced churn.
Finally, I refactored the apps to use TypeScript, which improved the code quality and significantly reduced the number of errors reported to Bugsnag. At the same time, it made onboarding new people to the project easier and gave more confidence to developers while developing new features.
The project sought a React web and mobile app in React Native. I was the lead JavaScript developer responsible for all web experiences, also helping with the mobile app.
I created and maintained internal npm packages that allowed better code sharing across multiple projects while managing and maintaining a responsive UI components library using Storybook.
I also worked on-sell pages, rewriting from legacy WordPress to Gatsby and React with static site generation backed by Sanity headless CMS that improved the page load speed and other key performance metrics.
Then, I designed and developed an A/B testing tool using Sanity CMS and Amplitude to test different versions of components across the web and mobile app, which led to increased revenue and reduced churn.
Finally, I refactored the apps to use TypeScript, which improved the code quality and significantly reduced the number of errors reported to Bugsnag. At the same time, it made onboarding new people to the project easier and gave more confidence to developers while developing new features.
Skills
Libraries/APIs
React, Node.js, React Router, Shopify API, Redux-Saga, jQuery
Tools
Webpack, Optimizely, GitHub, Prisma, Vagrant, Apache, NGINX
Languages
HTML5, CSS, JavaScript, TypeScript, SCSS, HTML, PHP
Frameworks
Jest, Redux, Next.js, React Native, Cypress, JSON Web Tokens (JWT)
Paradigms
Unit Testing, E2E Testing
Platforms
Sanity Studio, WordPress, Netlify, Shopify, Amazon Web Services (AWS), Contentful, Docker
Other
Storybook, Design Systems, UI Components, Chakra UI, Amplitude, Private NPM Modules, A/B Testing, Remote Team Leadership, Interviews, Gatsby, Styled-components, PSD to HTML
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